1. Field of the Invention
This invention is directed to a coaxial connector or connector system that can be employed to interconnect segments of a coaxial cable or an RF transmission cable. The invention is also related to a snap lock or snap-on configuration in which two coaxial connectors are mated by pushing them together without the need to screw one connector to a mating connector.
2. Description of the Prior Art
Coaxial connectors of many types are used to interconnect two coaxial cable segments or to interconnect a coaxial cable to a printed circuit board. Screw threaded connections and BNC style coaxial connectors provide a measure of mechanical security to the interconnection. Snap-on or snap lock connectors, however, provide a simpler means for making such a connection, requiring less mechanical manipulation. When a coaxial cable connection is part of an assembly operation or a larger component, a simple and fast connection has increased significance.
One means of forming a snap-on coaxial connector is to employ a metallic shell that is terminated at one end to the coaxial cable braid or outer conductor and which includes a plurality of spring fingers at the other end. The spring fingers can either encircle a corresponding surface on the mating connector or the spring fingers can fit into a ring on the other connector. Typically, the spring fingers will be deflected during initial mating, but when two coaxial connectors are fully mated, the spring fingers will, in a first or neutral position, fit into a groove, or recess or valley on the connector to which it is mated. A surrounding collar can be used in conjunction with a contact terminal or shell including spring fingers of this type. The collar can be axially shifted relative to the spring fingers so that in a second position, the spring fingers can be deflected during initial mating. After the spring fingers return to the first or neutral position, the collar shifts to a position that will prevent the spring fingers from being deflected out of engagement. To disconnect the two coaxial connectors, the collar must first be shifted to a position allowing the spring fingers to be radially deflected out of engagement with the groove or recess on the other connector. Typically, snap lock or snap-on coaxial connectors of this type employ a coil spring to provide a spring force between the shell and the collar. However, a connector of this type requires the assembly of numerous parts including a collar, a shell, a coil spring, spring washers or stops at either end of the spring, a pin to terminate the center contact and a dielectric to separate pin or stripped inner conductor from the outer shell and the braid to which it will be terminated. The shell and the collar for prior art connectors are also typically fabricated as metal components, with the most common fabrication techniques involving screw machining or die casting operations for the collar and the shell. Finally, some means must be provided for securing the collar to the shell as part of the fabrication assembly. For some coaxial connectors, employing cylindrical collars and shells, a post assembly, metal forming technique is used to attach the collar as part of the overall assembly. One such technique involves the step of rolling over or deforming one end of the collar to trap the coil spring in place. All of these assembly operations add cost to the final product.
Two examples of coaxial connectors employing a cylindrical metal collar and a cylindrical metal shell with deflectable spring fingers are shown in U.S. Pat. Nos. 4,017,139 and 5,316,494. The device shown in U.S. Pat. No. 4,017,139 employs spring fingers to fit within an annular groove on the mating jack connector to form a quick connect and quick disconnect configuration. U.S. Pat. No. 5,316,494 employs a metal collar and shell to mate with another coaxial connector that has external screw threads on a mating jack instead of a single annular groove.
Although these connectors have worked well for their intended applications, there is a need to reduce the cost of manufacture for connectors of this general type. Furthermore the increasing use of coaxial connectors in applications where the connection may be subjected to vibration has revealed another disadvantage with the use of metallic shells and collars for snap-on coaxial connectors. Where a coaxial connector is used to connect electronic equipment in an automobile, vibrations can cause an audible rattle between the metallic shell and collar for conventional snap-on connectors. Since these connectors are quite often used in or adjacent to the passenger compartment where electronic equipment, such as GPS based systems are mounted, this rattle can be objectionable. Because of the manufacturing tolerances that are used to fabricate cylindrical metallic shells and collars of this type it has proven difficult to eliminate this auditory rattle using conventional connectors. The present invention provides a means for simplifying manufacture of snap-on connectors and for eliminating the noise associated with all metal cylindrical coaxial cable assemblies without adversely affecting the electrical or mechanical integrity of the interconnection, while at the same time even further simplifying assembly of a plug coaxial connector to jack coaxial connector in an automobile or other large assembly.
This invention comprises a first coaxial connector, such as a plug, in which a first terminal, such as a plug shell, includes a deflectable locking member. The locking member engages a mating second terminal on a mating second coaxial connector, such as a jack connector. The first coaxial connector also includes a molded housing, which can function as a collar surrounding the shell. The first terminal is axially movable relative to the molded housing between a first, or neutral, and a second position, The locking member, which can be in the form of split cylindrical spring fingers, is deflectable when the first terminal and the molded housing are in the second relative position. The deflectable member is held in engagement with the second terminal by the molded housing when the first terminal and the molded housing are in the first relative position. The first coaxial connector also includes a spring, in the form of spring beams or an elastomeric member that engages with the first terminal to urge the first terminal and the molded housing toward the first or neutral position.
This coaxial connector can also be described as including a coax terminal shell with a generally cylindrical cross section and an outer collar surrounding the coax terminal shell. The outer collar includes a generally cylindrical inner surfaces on which the coax terminal shell is positioned and a upper and lower relatively noncircular exterior surfaces, which may be part of an overall rectangular shape. The outer collar comprises two separate housing components securable in surrounding relationship to the coax terminal shell in a position to permit relative movement between the coax terminal shell and the outer collar. The collar can be molded or fabricated in a different manner in accordance with the broader aspects of this invention.
This coaxial connector can include a snap lock shell attachable to an outer conductor in a coaxial cable and a collar axially shiftable relative to the shell. The snap lock shell has at least one radially deflectable member located on a mating end of the shell and radially extending lip, spaced from the deflectable member. The radially extending lip is trapped between springs, such as spring beams or elastomeric members, affixed to the collar. These springs generate a force between the shell and the collar for maintaining the shell and the collar in a relatively neutral position. The collar can be molded or fabricated in a different manner in accordance with the broadest aspects of this invention.